"I am next to you."
Translation:Jestem obok was.
It's "cię" vs "ciebie", so this shows that it's not any abbreviation.
Some of the personal pronouns have two or even three forms. In this example, the pronoun is in Genitive, as needed by the preposition "obok". The Genitive options for 2nd person singular are "cię" and "ciebie". The same two options are used for Accusative. Anyway, "cię" is neutral, and "ciebie" is emphatic.
That means that normally you will say "Szukam cię" (I am looking for you) or for example "Szukam go" (I am looking for him), but also "Szukam ciebie, a nie jego!" (I am looking for YOU, and not HIM!).